Eurostar services have resumed but some delays are expected until the end of Wednesday following two days of major disruption.
Wednesday saw knock-on disruption after two people died in separate incidents on the LGV Nord line the previous day, before services were further impacted by cable theft.
Eurostar had earlier urged passengers to postpone their journey as services were cancelled and delayed in both directions on lines connecting London with Paris, Brussels and Amsterdam.
On Wednesday evening, Eurostar said the line had been fully repaired and more cancellations were not expected, though some delays would continue throughout the evening.
The theft near Lille, which French media said was of around 600 metres of copper cables, caused trains to be rerouted, leading to extended journey times.
Five trains between London and Paris were cancelled.
It added that impacted passengers can change their travel plans for free or request a full refund.
“We’re very sorry for the impact this is having on our customers,” Eurostar said in a statement.
“Our teams are working closely with the French authorities and infrastructure teams to manage the situation and restore services safely.”
The operator earlier said one track had reopened, allowing some trains to run in both directions until full repairs were completed.
Water was being handed out to passengers onboard delayed trains, and stations are also very busy.
Hundreds of people were queuing at London’s St Pancras International railway station trying to access the service centre to rebook onto other trains.
Elizabeth Romijn, a yoga teacher from the Netherlands, told PA news agency at St Pancras that the situation was “very chaotic” and people were having to sit on the ground because there were not enough chairs.
The 75-year-old was planning to travel home to Brussels after visiting friends in Surrey.
“My plan is to just wait. Maybe I should go and be more proactive and go to ask one of the staff but nobody seems to know anything,” she said, adding that “it’s quite horrible long queues.”
The railway line in France was closed for much of the afternoon and evening on Tuesday after the two fatalities between Lille and Paris.
Services were cancelled on routes to and from Paris while trains between London, Brussels and Amsterdam ran with delays.
Eurostar said disruption continued into Wednesday as trains and crew were displaced.
